This application relates to an apparatus and method for identifying the presence of high conductivity or permittivity conditions in a wide range of electrically insulating materials and, more particularly, to a detector to assess the electrical integrity of a polymer insulator.
Insulators are utilized in many applications on transmission and distribution systems. The main application of an insulator is to mechanically attach current carrying conductors to support grounded structures while electrically insulating the conductors from the grounded structures.
Non-ceramic insulators (NCI) (also called polymer or composite insulators) are considered high risk if they contain internal or external defects of conductive or high permittivity. An example of a conductive defect would include internal carbonization of the fiberglass rod due to discharge activity, and an example of a high permittivity defect would be water internal to the insulator.
A requirement for ensuring worker safety when performing live work (LW) with polymer insulators is to confirm the short-term (i.e. for the duration of the work) electrical and mechanical integrity of both the installed and the replacement polymer units. Currently there are no generally accepted and easily applied procedures to accomplish this. Consequently, some utilities have opted not to use polymer insulators. In addition, a number of utilities that do use polymer insulators avoid live work on structures on which these insulators have been installed.
Accordingly, there is a need for an apparatus and method that can identify electrical and mechanical integrity of both installed and replacement polymer insulators.